Characterization of microbubble aggregation in a double-T microfluidic chip

The coalescence phenomenon of air bubbles affects the flow field, bubble morphology, bubble velocity, and mass transfer efficiency in bioreactors, air bubble generators, and other devices. This article combines the level set method with COMSOL to simulate the formation process of two-phase fluid bubbles in microfluidic chips. The result shows that when the contact angle exceeds 90°, significant agglomeration occurs and the size of bubbles decreases with the increase in liquid flow velocity. However, as the gas velocity increases, agglomeration does not occur at liquid flow rates below 0.1 m/s. In addition, the agglomeration phenomenon occurs above the threshold, and when the gas flow rate is less than 0.02 m/s, there is no agglomeration phenomenon. The numerical simulation results exhibit an error rate of less than 10% compared to the experimental values, indicating that microfluidic chips can accurately predict the process of bubble coalescence.